Quiz Discussion

SELECT instructor.*
FROM instructor, teaches
WHERE instructor.ID= teaches.ID;

This query does which of the following operation?

• 1]

  All attributes of instructor and teaches are selected

• 2]

  All attributes of instructor are selected on the given condition

• 3]

  All attributes of teaches are selected on given condition

• 4]

  Only the some attributes from instructed and teaches are selected

The most commonly used operation in relational algebra for projecting a set of tuple from a relation is

• 1]

  Join

• 2]

  Projection

• 3]

  Select

• 4]

  Union

Department (dept name, building, budget) and Employee (employee_id, name, dept name, salary)
Here the dept_name attribute appears in both the relations. Here using common attributes in relation schema is one way of relating ___________ relations.

• 1]

  Attributes of common

• 2]

  Tuple of common

• 3]

  Tuple of distinct

• 4]

  Attributes of distinct

SELECT name ____ instructor name, course id
FROM instructor, teaches
WHERE instructor.ID= teaches.ID;

Which keyword must be used here to rename the field name?

• 1]

  From

• 2]

  Rename

• 3]

  As

• 4]

  Join

A ________ in a table represents a relationship among a set of values.

• 1]

  Column

• 2]

  Key

• 3]

  Row

• 4]

  Entry

The term _______ is used to refer to a row.

• 1]

  Attribute

• 2]

  Tuple

• 3]

  Field

• 4]

  Instance

SELECT name
FROM instructor
WHERE salary <= 100000 AND salary >= 90000;

This query can be replaced by which of the following ?

• 1]

  SELECT name
  FROM instructor
  WHERE salary BETWEEN 90000 AND 100000;

   

• 2]

  SELECT name
  FROM employee
  WHERE salary <= 90000 AND salary>=100000;

   

• 3]

  SELECT name
  FROM employee
  WHERE salary BETWEEN 90000 AND 100000;

   

• 4]

  SELECT name
  FROM instructor
  WHERE salary BETWEEN 100000 AND 90000;

   

The _______ operator takes the results of two queries and returns only rows that appear in both result sets.

• 1]

  Union

• 2]

  Intersect

• 3]

  Difference

• 4]

  Projection

Course(course_id,sec_id,semester)

Here the course_id,sec_id and semester are __________ and course is a _________

• 1]

  Relations, Attribute

• 2]

  Attributes, Relation

• 3]

  Tuple, Relation

• 4]

  Tuple, Attributes

A ________ is a pictorial depiction of the schema of a database that shows the relations in the database, their attributes, and primary keys and foreign keys.

• 1]

  Schema diagram

• 2]

  Relational algebra

• 3]

  Database diagram

• 4]

  Schema flow